An integrated circuit (IC) package can include multiple IC dies disposed on a substrate. A heat spreader, also known as a cover or lid, can be mounted to the substrate to cover the multiple IC dies. A thermal interface material can be disposed between the IC dies and the cover. An assembly process for attaching the cover to an IC package includes the application of a mechanical force to the cover at an elevated temperature. The IC packages typically have some warpage at room temperature prior to mounting the cover. After heating while mounting the cover, the warpage of the IC packages may by exasperated. Further, there are variations in the flatness of the cover, the assembly tools used while mounting the cover to the IC package, and the force applied to the cover during assembly. These variations in flatness, when combined with the change in curvature of the IC packages during assembly, result in application of non-uniform force to the IC packages and non-uniform heating of the IC packages. The non-uniform application of force and heating can cause mechanical stresses in the IC packages, which may result in cracking and/or delamination. Further, the amount of thermal interface material disposed between the IC dies and the cover may not be uniform due to the aforementioned variations, thus creating areas of higher thermal resistance, i.e., hot spots, in certain locations of the IC packages.
Thus, there is a need for an improved IC package, along with methods and tools for fabricating the same.